* {
    margin: 0;
    padding: 0;
}

ul li {
    list-style: none;
}

main {
    width: 960px;
    height: 500px;
    border-radius: 10px;
    margin: 50px auto;
}

main h4 {
    height: 100px;
    line-height: 100px;
    text-align: center;
}

.tabsbox {
    width: 900px;
    margin: 0 auto;
    height: 400px;
    border: 1px solid #ccc;
    position: relative;
}

nav ul {
    overflow: hidden;
}

nav ul li {
    float: left;
    width: 100px;
    height: 50px;
    line-height: 50px;
    text-align: center;
    /* border-right: 1px solid #ccc; */
    position: relative;
    user-select: none;
    cursor: pointer;
}

nav ul li.liactive {
    border-bottom: 2px solid orangered;
    z-index: 9;
    background-color: rgba(0, 0, 0, .1);
}

.tabsbox input {
    width: 80%;
    height: 60%;
}

nav ul li span.close {
    position: absolute;
    user-select: none;
    font-size: 14px;
    top: 0;
    right: 0;
    line-height: 1;
    height: 20px;
    width: 20px;
    height: 20px;
    display: none;
    color: red;
}

nav ul li span.edit {
    position: absolute;
    user-select: none;
    font-size: 12px;
    top: 28px;
    right: 0;
    line-height: 1;
    height: 20px;
    width: 20px;
    height: 20px;
    display: none;
    color: green;
}

nav ul li:hover {
    background-color: rgba(0, 255, 0, .1);
}

nav ul li:hover span.close,
nav ul li:hover span.edit {
    display: block;
}

.tabadd {
    position: absolute;
    /* width: 100px; */
    top: 0;
    right: 0;
}

.tabadd span {
    display: block;
    width: 20px;
    height: 20px;
    line-height: 20px;
    text-align: center;
    border: 1px solid #ccc;
    float: right;
    margin: 10px;
    user-select: none;
}

.tab-content {
    width: 100%;
    height: 300px;
    position: absolute;
    padding: 30px;
    top: 50px;
    left: 0px;
    box-sizing: border-box;
    border-top: 1px solid #ccc;
}

.tab-content section,
.tab-content section.conactive {
    display: none;
    width: 100%;
    height: 100%;
}

.tab-content section.conactive {
    display: block;
}

.tab-content section textarea {
    width: 500px;
    height: 300px;
    resize: none;
}

.edit-title {
    width: 80%;
    height: 20px;
}